Primary open angle glaucoma

Primary open angle glaucoma, sometimes called chronic open angle glaucoma, is the most common type.

In this type of glaucoma, the part of the eye where fluid drains away (called the "angle") isn't blocked, but the fluid doesn't drain properly. This leads to increased pressure in the eye.

The condition usually develops very slowly over many years and doesn't cause any noticeable symptoms at first.

People often don't realise they have it because the outer areas of vision (peripheral vision) are affected first. Without treatment, vision towards the centre of the eye may also be lost.

Primary open angle glaucoma is usually picked up during a routine eye test, which you should have at least every two years. Visit an opticians or your GP if you're worried about any changes in your vision.

Primary angle closure glaucoma

Primary angle closure glaucoma is a less common type that occurs when the part of the eye that drains fluid becomes blocked, causing pressure to build up in the eye.

It occasionally develops slowly over time, but often it causes sudden, severe symptoms.